Mattress



FIG. 1 is a perspective view of the mattress.

FIG. 2 is a side view of the mattress of FIG. 1, identical to the opposite side thereof.

FIG. 3 is an end view of the mattress of FIG. 1, identical to the opposite end thereof.

FIG. 4 is a top view of the mattress of FIG. 1; and,

FIG. 5 is a bottom view of the mattress of FIG. 1.

The broken lines are for environmental purposes only and form no part of the claimed design. 

CLAIM The ornamental design for a mattress, as shown and described. 